Before you even think about batch uploading a set of files, be 100% sure all the files are free and fall within the project scope. Make sure you know the artists and when they died or which century they lived in and use creator templates to allow others easily verify the year of death. If you need to arrange permission, please do so before starting the batch upload. In most cases each batch upload will use a single license for the whole batch. Which license is appropriate depends on a variety of factors, especially whether the images are of 2D objects or 3D objects.

2D works include paintings, drawings, photographs, and documents. If you intend to use one of the licenses below, make sure the images are actually 2D; try to crop frames of paintings if present, do not upload photographs of rooms with murals or frescoes if they show architectural features unless you provide a separate license for the photographer. Some appropriate licenses for 2D works include:

{{PD-Art}} - use for images of 2D artworks by artists who died more than 70 years ago.

{{Licensed-PD-Art}} - use for images of 2D artworks by artists who died more than 70 years ago when the photographer of the work has explicitly released their photographs under a free license.

{{PD-scan}} - use for scans or photocopies of 2D works by authors who died more than 70 years ago.

All of these templates can be passed a sub-license as a parameter. For example, if you are uploading images of paintings and you know that all of the artists died at least 100 years ago, you could use {{PD-Art|PD-old-100}}

3D works include sculptures, buildings, paintings with artistic frames, coins, and some textiles. In most cases, two copyrights will be involved in these images: a copyright on the original work and a copyright on the photograph itself. (See Commons:Freedom of panorama for exceptions.) When you upload the images, be sure to specify the licensing for both the photograph and the work depicted in the photograph. See, for example, this photo of a 3D artwork from the Walters Art Museum. 3D works generally don't require specialized licensing tags. You can usually use standard PD-Old tags for the works and Creative Commons tags for the photographs.

Before you upload anything you need to have the files. You can either have the files stored locally or have URL links to the exact location of the source files. The URL should deep link directly to the jpg/ogg/... files. In case all or some of the images need to be altered, for example to crop frames of the paintings or remove watermarks, then it is easier to download all the images first and store them locally.

Get the metadata so we have enough information to later construct the filename, description and categories. For example in case of artworks you might need: authors, titles, techniques, dates, institutions holding the artwork, etc. Sources of metadata might include:

Descriptions should be derived from the metadata, especially if there is extensive metada provide by a partner institution. To successful store the information on Commons, the metadata will need to be converted into wikitext format:

Best practice is to use standardized templates for the metadata to ensure that the metadata has a longer, more robust sustainability on Commons (esp. as Commons:Structured data becomes possible):

The files you're going to upload need to get integrated into the category tree on Commons. Categories are a common way for users to find files. A full categorization as possible is key to getting your images seen by the widest audience.

Origin category can be further divided in tracking categories and source categories. Tracking categories are of little use to 'normal users', but are essential for tracking all content from a source. For example, the BaGLAMa tool uses this category to provide monthly page views.

A tracking category can also indicate that the reproduction is 'officially donated'. Reproductions (especially of public domain works) can be found widely on the internet and uploaded by any Commons users. In the case of a batch upload, the source is usually 'verified' (e.g. via an API or a datadump). It therefore makes sense to have both a tracking category such as Media contributed by <institution> and a source category indicating the collection of that institution such as Collections of <institution>.

As many topic categories as possible from the metadata. These may include, as appropriate: date (Category:1905 in France), location, place of creation, artist, type of object, style, material, technique, subject, etc. Ideally use as precise a category as possible within each tree (check what sub-categories there are), and if a large number of files - say over 20, but sometimes fewer - are going to be added to a category, it is often best to either spread them among subcategories, or create a new sub-category for them (as was done with subcategories of Category:Photographs by Paolo Monti).

{{subst:chc}} to add {{Check categories}} automatically (HotCat and others will remove it automatically when categories are altered manually). And/or a «To check» category for the post-upload maintenance (see Category:To be checked).

Upload a few images, and ask for feedback on the Commons:Batch uploading subpage. Reviewers will point out or come up with some crazy and unheard-of templates that you will want to integrate. You will certainly have to go through several iterations before you have the green light. Please be patient: it is better to get it right the first time than to fix uploads afterwards.

If you want to test uploading and safely experiment with using tools or new templates in a safe environment, you can set up an account on the beta cluster. This is a mirror of Wikimedia Commons where if things go wrong you will not cause any disruption to the live environment. See http://commons.wikimedia.beta.wmflabs.org and this explanation.